ASHRAE Journal - May 2022 - 26

ENGINEER'S NOTEBOOK
COLUMN
Elevator HVAC
Design Requirements
BY KELLEY CRAMM, P.E., MEMBER ASHRAE; BRAD CHAMBON, P.E., MEMBER ASHRAE
Elevators are a staple in most modern buildings of more than one story. Chapter 30 of
the International Building Code (IBC) and American Society of Mechanical Engineers
(ASME)-A17.1 Safety Code for Elevators and Escalators both cover elevator requirements.
The increased application of machine room-less elevators has resulted in confusion on
how to apply code requirements when there is no machine room. This column discusses
mechanical design considerations for elevators, code and ASME implications, and architectural
coordination. It does not address elevators in high-rise buildings, which the IBC
defines as " a building with an occupied floor located more than 75 ft (22 860 mm) above
the lowest level of fire department vehicle access. "
Mechanical Design Considerations
Hoistway Venting
Please note that the following information on hoistway
venting is taken from the 2012 International Building
Code. The 2015 and later versions of the International
Building Code do not include the section on " Hoistway
Venting. " The 2015 commentary states the following:
" Hoistway venting was deleted, as it seemed counterintuitive
to the need for enclosed elevator lobbies in the
code. The provisions were historic in nature and were
provided for the fire service, but they were no longer
seen as necessary. In addition, the hoistway venting
requirements often conflicted with the hoistway pressurization
option for elevator lobby enclosures. "
You should always examine the specific code that
applies to your project to determine if you are required to
provide hoistway venting. Some local municipalities may
be stricter than the IBC and may require hoistway venting
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ASHRAE JOURNAL ashrae.o rg M AY 2022
with no exceptions. Many jurisdictions are still under the
2012 codes, which may require hoistway venting.
The purpose of hoistway venting is to allow smoke
and hot gases to vent out of the elevator hoistway to the
outside in the event of a fire. Contrary to popular belief,
hoistway venting is not to allow the air to push and pull
out of the hoistway due to piston effects so the elevator
can operate correctly. If this were the case, the IBC
would not allow exceptions. Note that hoistway venting
requirements apply to traditional elevators with
machine rooms and to machine room-less elevators.
The first criteria for hoistway venting is the number
of floors the elevator serves. Note that in the code the
word " serves " does not mean what floors the elevator
opens to. An elevator that goes between the first floor
and fifth floor, but only opens to the first floor and the
Kelley Cramm, P.E., is an associate and mechanical technical manager, and Brad
Chambon, P.E., is a mechanical technical manager at Henderson Engineers in
Lenexa, Kan.

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ASHRAE Journal - May 2022

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